(D) Another repeating transformation is the reductive amination that shows up in the Schemes 3, 5 and 6. This takes Ar-NH₂ to Ar-N(CH3)2 with NaBH4/HCHO (formaldedyde). This provides the "rear" dipole that drives the nanocar. Show the mechanism for converting Ar-NH₂ → Ar-N(CH3)2 with two formaldehyde molecules and NaBH4. You will need to review your notes from lab5 in

A special case of alcohol dehydration is a reaction called the pinacol rearrangement. A molecule called pinacol, a diol (a molecule with two OH groups) is heated in the presence of sulfuric acid. The mechanistic steps are the same as you have seen for alcohol dehydration. The product, pínacolone, features a new C-O bond rather than the new C-Cл bond that is usually formed in alcohol dehydration. 1st attempt tox AN → i H-O 1 See Periodic Table See Hint 1

3. A key transformation in the original synthesis of cocaine was the synthesis of 1,3- cyloheptadiene from cycloheptanol. Show how this could be accomplished. We have provided you one of the necessary synthetic steps. он Br Br Me2N Me,NH (you need to use this reaction) ÇO,Me -N- OBz cocaine Today 10:59:36 PM

Write out the last 3 steps only of the 6-step arrow pushing mechanism showing how acetic acidand methanol combine in the presence of a catalytic amount of H+to form an ester:

I don't even know how to begin this synthesis.  Does the initial attack by the oxygen of the H on the HCl lead to the formation of the OH group in the carboxylic acid or the OH group on the primary alcohol groups?

(b) Identify the reagents you would use to convert pentanoic acid into 1-pentene. Pentanoic acid → 1-pentene The transformation above can be performed with some reagent or combination of the reagents listed below. Give the necessary reagents in the correct order, as a string of letters (without spaces or punctuation, such as "EBF"). If there is more than one correct solution, provide just one answer. A. TsCl, pyridine D. H3O+, heat G. t-BuOK B. NaCN E. PBr3 H. 1) LIAIH4; 2) H3O+ C. NaBH4, MeOH F. NaOEt I. 1) BH3-THF; 2) H₂O2, NaOH